The goal of the research proposed in this application is to delineate the tumor-associated changes found in human colorectal cancer cells with particular emphasis on alterations in the structure, antigenicity and metabolism of cellular glycoconjugates. This study will help solve two important problems in human colorectal cancer: the development of sensitive, specific markers for the early stages of the disease and the elucidation of the molecular mechanisms involved in carcinogenesis. Glycoconjugate will be selected for purification and characterization based on three systems of comparison: the differences between normal and cancerous tissues; between colon cancer cells treated with differentiating agents or tumor promoters and untreated cells; among clones of colorectal cancer cells selected for differences in their metastatic potentials. Studies have already shown tht two specific differences between normal and cancerous tissues are the lectin-binding patterns of the mucosa cell mucins and the expression of an antigen which cross-reacts with antibody against mouse embryo differentiation stage-specific antigen (SSEA-1) in colon cancer tissue but not in normal colon. The glycoproteins responsible for these properties and others of significance will be purified using conventional technqiues of chromatography and electrophoresis. In addition, lectin- and antibody-affinity chromatographic methods will also be used. As an aid to the purification and for the use later in tghe quantitation of antigens of interest, monoclonal and polyclonal antibodies will be raised against the starting materials and against purified glycoconjugates. Glycolipids will be purified by solvent extraction followed by preparative thin layer chromatography and high-performance liquid chromatography (HPLC). The oligosaccharide structures of the purified glycoconjugates will be analyzed by chemical cleavage and radiolabeling following by paper electrophoresis, column chromatography gas-liquid chromatography - mass spectrometry and analytical HPLC. The treatment of cells with differentiating agents will be performed using sodium butyrate, dimethylsulfoxide and retinoic acid. It is felt that the results obtained using these techniques will improve the diagnosis, prognosis and treatment of human colorectal cancer.